constant-current-voltage-subthalamic-dbs-pd-nct06742450

Constant Current vs Voltage Subthalamic DBS for Parkinson's Disease (NCT06742450)

Overview

NCT06742450 is a randomized, parallel-controlled, multi-center clinical trial comparing constant current (CC) versus constant voltage (CV) modes of deep brain stimulation (DBS) in patients with Parkinson's disease. The study aims to compare efficacy, programming burden, power consumption, and physician/patient satisfaction between the two stimulation modalities.

Deep brain stimulation (DBS) has revolutionized the treatment of advanced Parkinson's disease, providing significant improvements in motor function, medication reduction, and quality of life for patients who have exhausted optimal medical therapy. Despite its widespread adoption, fundamental questions remain about optimal stimulation parameters and hardware configurations. This trial addresses one such critical question: whether constant current or constant voltage stimulation provides superior clinical outcomes.

Trial Details

Constant Current vs Voltage Subthalamic DBS for Parkinson's Disease (NCT06742450)

Overview

NCT06742450 is a randomized, parallel-controlled, multi-center clinical trial comparing constant current (CC) versus constant voltage (CV) modes of deep brain stimulation (DBS) in patients with Parkinson's disease. The study aims to compare efficacy, programming burden, power consumption, and physician/patient satisfaction between the two stimulation modalities.

Deep brain stimulation (DBS) has revolutionized the treatment of advanced Parkinson's disease, providing significant improvements in motor function, medication reduction, and quality of life for patients who have exhausted optimal medical therapy. Despite its widespread adoption, fundamental questions remain about optimal stimulation parameters and hardware configurations. This trial addresses one such critical question: whether constant current or constant voltage stimulation provides superior clinical outcomes.

Trial Details

| Field | Value |
|-------|-------|
| NCT Number | NCT06742450 |
| Status | Recruiting |
| Phase | Not Applicable (Device Study) |
| Enrollment | 180 participants (estimated) |
| Study Type | Interventional |
| Allocation | Randomized |
| Intervention Model | Parallel |
| Masking | Double-blind (Participant, Outcomes Assessor) |
| Start Date | January 27, 2024 |
| Primary Completion | March 31, 2026 |
| Completion Date | August 31, 2026 |
| Sponsor | Xuanwu Hospital, Beijing |
| Collaborators | Beijing Pins Medical Co., Ltd; Chinese PLA General Hospital; Tianjin Huanhu Hospital; and 10 additional sites |

Scientific Rationale

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established treatment for advanced Parkinson's disease[@dbs_mechanisms][@stn_dbs_outcomes]. The therapy delivers electrical pulses to targeted brain regions, modulating abnormal neural activity and restoring more normal motor circuit function. Two primary stimulation modalities are available:

Constant Voltage (CV) Mode

The traditional approach used in most DBS systems, constant voltage mode maintains a fixed voltage output at the electrode-tissue interface[@volkmann2013]:

• Fixed voltage output: The device maintains a predetermined voltage level
• Variable current: Current varies based on electrode impedance
• Clinical experience: Decades of use in millions of DBS procedures
• Impedance drift: Tissue changes around electrodes can alter delivered current
• Programming considerations: Requires careful impedance monitoring

Constant Current (CC) Mode

A more recent innovation, constant current mode maintains a fixed current output regardless of impedance changes[@constant_current_dbs]:

• Fixed current output: The device maintains a predetermined current level
• Adaptive voltage: Voltage automatically adjusts to maintain consistent stimulation
• More stable delivery: Therapeutic dose remains consistent over time
• Reduced reprogramming: May decrease need for frequent parameter adjustments
• Power consumption: May be higher or lower depending on impedance

• Tissue fibrosis around the electrode
• Changes in electrode encapsulation
• Cellular responses to chronic stimulation
• Foreign body reactions

Why This Comparison Matters

This head-to-head comparison is clinically significant because:

Intervention Description

Constant Current Arm

For subjects who have decided to undergo STN-DBS surgery and meet inclusion criteria, the constant current (CC) mode is selected as the stimulation modality one week after surgery. Regardless of any changes in programming parameters over the following year, the constant current (CC) mode will be maintained. Participants will undergo standard postoperative programming sessions to optimize their therapeutic window.

Constant Voltage Arm

For subjects who have decided to undergo STN-DBS surgery and meet inclusion criteria, the constant voltage (CV) mode is selected as the stimulation modality one week after surgery. Regardless of any changes in programming parameters over the following year, the constant voltage (CV) mode will be maintained.

Standard Surgical Procedure

Both groups undergo identical surgical procedures:

Eligibility Criteria

Inclusion Criteria

• Patients with idiopathic Parkinson's disease
• Aged 18 to 75 years
• After bilateral STN-DBS implantation, yet not powered on
• Able to provide informed consent
• Willing to comply with follow-up schedule

Exclusion Criteria

• Mental disorders or dementia (MMSE <24)
• Pregnant, lactating women, or women unable to take effective contraception
• Serious health conditions (tumors, liver or kidney diseases)
• Epilepsy or other seizure disorders
• Severely deviated electrode placement
• Unable to voluntarily sign informed consent
• Unable to cooperate with follow-up
• Prior DBS surgery
• Active psychiatric comorbidities

Outcome Measures

Primary Outcome

• Change rate of MDS-UPDRS III (Motor Examination)
• Timeframe: from baseline to 6 months after surgery
• MDS-UPDRS III ranges from 0-132 and provides objective assessment of motor symptoms

Secondary Outcomes

| Measure | Timeframe | Description |
|---------|-----------|-------------|
| MDS-UPDRS I | 6 months | Non-motor experiences of daily living |
| MDS-UPDRS II | 6 months | Motor experiences of daily living |
| MDS-UPDRS IV | 6 months | Motor complications (dyskinesias, fluctuations) |
| Clinical Global Impression (CGI) | 6 months | Overall clinical assessment |
| Physician satisfaction feedback | 6 months | Structured programming experience survey |
| Patient satisfaction feedback | 6 months | Treatment experience questionnaire |
| Power consumption | 6 months | Device battery metrics |
| Impedance measurements | 6 months | Electrode-tissue impedance |
| Adverse effects | 12 months | Safety monitoring |

Assessment Schedule

| Visit | Timing | Assessments |
|-------|--------|-------------|
| Screening | Pre-surgery | Medical history, cognitive assessment, imaging |
| Surgery | Day 0 | Bilateral STN-DBS implantation |
| Activation | Day 7 | Device activation, initial programming |
| Month 1 | Week 4 | Clinical assessment, optimization |
| Month 3 | Week 12 | Primary and secondary endpoints |
| Month 6 | Week 24 | Comprehensive outcome assessment |
| Month 12 | Week 48 | Final safety assessment |

Clinical Translation

Biomarker Connections

Imaging Biomarkers

• Post-operative CT/MRI for electrode localization
• Diffusion tensor imaging for white matter tract visualization
• FDG-PET for network-level changes

• Levodopa challenge response
• Motor fluctuations and dyskinesia diaries
• Sleep quality assessments (PDSS-2)

• Local field potential recordings (research setting)
• Impedance measurements over time
• Stimulation threshold assessments

Patient Impact

Potential Benefits of Each Mode

| Aspect | Constant Current | Constant Voltage |
|--------|-----------------|------------------|
| Dose stability | Consistent over time | Varies with impedance |
| Programming ease | May need less adjustment | Requires impedance monitoring |
| Battery life | Variable | Often longer at low impedance |
| Flexibility | Fixed current, variable voltage | Fixed voltage, variable current |
| Clinical data | Growing evidence | Extensive long-term data |

Challenges

• Both require expert programming
• Individual response varies significantly
• Hardware limitations may restrict options
• Long-term maintenance considerations

Mechanistic Pathways

Quality of Life Considerations

DBS impacts multiple domains of quality of life[@rektorova2015]:

Motor Benefits

• Reduced "off" time
• Decreased dyskinesias
• Improved mobility
• Reduced medication needs

• Improved sleep
• Better mood
• Enhanced cognition (in some patients)
• Increased independence

• Surgical complications (bleeding, infection)
• Hardware complications (lead fracture, infection)
• Neuropsychiatric effects
• Speech and gait effects
• Cognitive decline (rare)

Research Context

Supporting Evidence

STN-DBS Efficacy
Multiple randomized controlled trials have demonstrated STN-DBS efficacy[@Deuschl2006][@morrell2011]:

• Significant improvement in motor function (30-60% reduction in MDS-UPDRS III)
• Reduced motor fluctuations and dyskinesias
• Improved quality of life measures
• Reduced medication requirements
• Long-term durability (10+ years in many patients)

• Small crossover studies suggest similar efficacy
• Impedance stability varies between patients
• Programming satisfaction may favor constant current
• Need for large definitive trials

Competitive Landscape

| Device | Manufacturer | Current Mode | Voltage Mode | Key Features |
|--------|-------------|-------------|--------------|---------------|
| RC | Boston Scientific | Yes | Yes | Directional leads |
| Infinity | Abbott | Yes | Yes | Bluetooth programming |
| Activa | Medtronic | No | Yes | Longest clinical history |
| Pins | Beijing Pins | Yes | Yes | Chinese manufacturer |

Future Directions

The field of DBS continues to evolve:

• Adaptive DBS: Closed-loop systems that respond to neural signals
• Directional leads: Steering stimulation to reduce side effects
• Multi-target approaches: Simultaneous stimulation of multiple regions
• Battery-free systems: Energy harvesting and wireless power
• Biomarker integration: Using neural signals for programming

Related Pages

• [Deep Brain Stimulation](/therapeutics/deep-brain-stimulation)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Subthalamic Nucleus](/brain-regions/subthalamic-nucleus)
• [Circuit-Based DBS for Parkinson's Disease](/clinical-trials/circuit-based-dbs-parkinson)
• [DBS-NBM for Parkinson's Disease (NCT07218081)](/clinical-trials/dbs-nbm-nct07218081)

References

External Links

• [ClinicalTrials.gov: NCT06742450](https://clinicaltrials.gov/study/NCT06742450)
• [Xuanwu Hospital, Beijing](https://www.xuanwu.edu.cn/)